The present invention relates to a tube connection structure for endoscope, and particularly to a tube connection structure for connecting a flexible tube, which is used for endoscopes, treatment accessories and/or light source devices, with a connection member.
Conventionally, flexible tubes have been broadly used for endoscopes, treatment accessories and/or light source devices for endoscopes. Generally, one end of such a flexible tube is connected with a connection member.
A simple example known as a connection member is a pipe-shaped connection member, which is merely press-inserted in one end of a flexible tube. Another example is a connection member formed with an opening, in which one end of the flexible tube is merely inserted.
Further examples are: a connection member formed with a screw portion, which is screw-inserted in the end of the flexible tube; and a connection member having inside and outside tapered tubes which are screwed and engaged with each other, with the end of the flexible tube nipped therebetween.
In the former two examples, if the flexible tube is drawn strongly, the tube may be removed from the connection member. Therefore, such a structure should be used only in portions where the strong force may not be applied to the flexible tube.
In the latter two examples, since the structure includes a screw portion, whose diameter may be relatively large, positions where such a structure is used are limited.
It is therefore an object of the present invention to provided an improved tube connection structure for an endoscope to connect a flexible tube to a connection member, in which the connection part is not too thick, and enabling a sufficient connection strength.
For the above object, according to the present invention, there is provided a tube connection structure for an endoscope system for connecting a flexible tube with a connection member. The structure includes a rigid cylindrical member tightly inserted in an end portion of the flexible tube. The connection member is provided with an opening for receiving the end portion of the flexible tube in which the rigid cylindrical member is tightly inserted. The diameter of the rigid cylindrical member is designed such that the flexible tube is tightly nipped between the rigid cylindrical member and an inner surface of the opening of the connection member.
With this structure, the connection part will not become too thick, with enabling a sufficient connection strength between the flexible tube and the connection member.
Optionally, an outer diameter of the cylindrical member may be substantially constant at any position along the axis thereof, and an inner diameter of the opening may be substantially constant at any position along the axis thereof.
Further optionally, the inner diameter of the cylindrical member may be substantially equal to an inner diameter of the flexible tube.
In a particular case, a thickness of a wall of the cylindrical member is within a range of 0.05 mm through 0.3 mm.
Still optionally, the flexible tube may be a sheath of a treatment accessory for an endoscope.
Alternatively, the flexible tube may be a tube to be inserted in a forceps channel of an endoscope.